The Value of Fusional Convergence Amplitudes in Esodeviation Surgery without Adjustable Sutures
Anu Maudgil, FRCOphth; Naz Raoof, FRCOphth; John P. Burke, FRCOphth
Royal Hallamshire Hospital
Introduction: Ongoing debate exists in the literature over whether adjustable suture utilization achieves binocular single vision (BSV) more consistently than non-adjustable surgery. We explored whether for certain esodeviation sub-groups, using the magnitude of individual fusional amplitudes when choosing a surgical target angle (TA) would prove efficacious without utilizing adjustable sutures.
Methods: Thirty-one consecutive cases of presumed acquired non-accommodative, deteriorated intermittent esotropia managed surgically between 2005- 2016 were reviewed retrospectively. For each individual, TA was selected pre-operatively after analysis of fusional convergence amplitudes. Outcomes in patients selected for overcorrection at 6 meters, (TA > angle in primary position at 6 meters (PPA)), were compared to those who had planned surgery based on a TA that did not exceed their measured angle (TA</= PPA) at 6 meters.
Results: All 31 patients achieved BSV in primary position both at near and at 6 meters without prisms, orthoptic therapy or additional surgery at 4-6 months post-operatively. There was a trend towards a greater correction in the TA>PPA group compared to TA</=PPA group, but this difference was not statistically significant (p=0.57).
Discussion: Amongst this diagnostically specific cohort of intermittent esotropes with symptomatic diplopia and measurable BSV preoperatively, targeted surgery based on analysis of pre-existing fusional convergence amplitudes had an outcome that compared favorably to that of documented adjustable suture strabismus surgery.
Conclusion: While we recognize the benefits of adjustable sutures in complex cases with less robust BSV potential, categorizing esodeviations by their aetiology and BSV potential allows suitable cases to be planned for non-adjustable suture surgery, achieving successful outcomes by economical and subjectively less stressful means.